This invention relates to processes for the production of polymers from aromatic compounds. In one of its aspects, this invention relates to processes for the production of arylene sulfide polymers. In another of its aspects, this invention relates to the separation of solid and liquid components of the reaction mixture of the reaction of polyhalo-substituted aromatic compounds in polar organic solvent to provide poly(arylene sulfide). In still another of its aspects, this invention relates to the recovery of relatively large particulate poly(arylene sulfide) from its reaction mixture. In still another aspect of the invention, it relates to the recovery of particulate poly(arylene sulfide) by separation from the other components of its reaction mixture.
In one concept of this invention it provides a method for separating the reaction mixture of the reaction of polyhalo-substituted aromatic compounds and polar organic solvent which has produced poly(arylene sulfide) into a particulate poly(arylene sulfide) that is recovered from the reaction mixture and other components that can be separated for recovery or disposal.
A basic process for the production of arylene sulfide polymers from polyhalo-substituted cyclic compounds containing unsaturation between adjacent ring atoms, wherein the halogen atoms attached to ring carbon atoms react with an alkali metal sulfide in a polar organic compound at an elevated temperature is disclosed in U.S. Pat. No. 3,354,129. Since the disclosure of that invention a great amount of experimental work has been completed which resulted in the disclosure of methods for both batch and continuous operations to produce poly(arylene sulfides) not only from p-dihalobenzenes but also containing polyhalo aromatic compounds having more than two halogen substituents per molecule and with the addition of various polymerization modifying compounds such as alkali metal carboxylates. Processes have also been disclosed in which various reactants can be premixed to form reaction complexes before all of the reactants are brought together at polymerization conditions. All of these processes have in common the production at a temperature above that at which poly(arylene sulfide) is in molten phase, of a reaction mixture containing poly(arylene sulfide) and a polar organic solvent along with various impurities and unreacted reactants from which solid poly(arylene sulfide) is recovered.
In the past a solvent flashing process has generally been used to recover a powdery resin from the reaction mixture. This powdery resin has proved to be difficult to filter from the arylene sulfide oligomers that are byproducts of the polymerization, has resulted in a product that when dried is excessively dusty, has necessitated pelletizing the powder for extrusion purposes, and has resulted in other problems commonly associated with products of relatively low bulk density. Increasing the size of the particulate poly(arylene sulfide) produced from the processes described above would result in alleviating these problems. The present invention provides a process by which arylene sulfide polymers having relatively larger, coarser particles can be recovered from reaction mixtures containing poly(arylene sulfide) and polar organic solvent.
It is therefore an object of this invention to provide a method for recovering relatively large, granular poly(arylene sulfide) particles from a reaction mixture containing poly(arylene sulfide) and polar organic solvent. It is another object of this invention to provide a method for recovering poly(arylene sulfide) having a particle size distribution resulting in improved filterability and reduced dustiness as compared to the resin recovered by solvent flashing methods. It is still another object of the invention to provide a method for recovering poly(arylene sulfide) having a particle size distribution that will eliminate the need for pelletizing the recovered particles prior to extrusion. It is still another object of the invention to produce poly(arylene sulfide) having a generally higher bulk density than is produced by solvent flashing methods of recovering the polymer from its reaction mixture. It is still another object of this invention to provide a method for recovery of poly(arylene sulfide) which facilitates separation of arylene sulfide oligomers from the reaction mixture. It is another object of this invention to produce useful manufactured articles from poly(arylene sulfide) recovered by the method of this invention.
Other aspects, concepts, and objects of this invention will become apparent to those reading this disclosure and studying the appended drawings and claims.